A single catalog does make sense, thanks for the sanity check reply.
I can allot 75GB of SSD storage space to catalogs. The current laptop catalog previews are 12GB and the old workstation previews are 70GB, but if memory serves correct, I had selected "never" for "automatically discard 1:1 previews". For the new catalog I intend to set file handling to: 1680 pixels / medium / discard 1:1 after 30 days. My monitors are 1920x1200, so I figure that 1680 is larger than viewed images after subtracting for the usual menu size.
The SSD is 256GB but the rest of the space is used for boot and engineering working files. I'm figuring on replacing the existing 7200rpm 500GB HDD with a 1TB, and considering a new Western Digital AV-25 WD10JUCT drive. That's where current year photos will store.